Ruby Combination Generator

ruby_combination_generator.rb

# uses gem combination_generator
# generates all possible 8 character combinations for letters A-Z
# writes combinations to file combinations.txt 

require 'combination_generator'

alphabet = ('a'..'z').to_a.map(&:upcase!)
combinations = []
CombinationGenerator.new(8, alphabet).each {|combo| combinations << combo }
f = File.new 'combinations.txt', 'w'
f.write(combinations)
f.close